1. Muscular System

2. Types of muscle tissue Muscle tissue has the function of movement
There are 3 types of tissue
Skeletal
Attached to bones - moves bones
Voluntary control
Cells are striated (striped) and long (muscle fibers)
Smooth muscle
Line the tubes in your body (digestive tract, arteries, etc) - pushes stuff through tubes
Involuntary
Cells are spindle shaped, not striated
Cardiac muscle
Found in heart - makes heart beat
Cells are striated but short

3. Skeletal muscles, muscle tissue, muscle cells
Muscles are made of BUNDLES of muscle fibers
Muscle fibers ARE muscle cells
The muscle cells are filled with protein cables called filaments

4. How muscles and bones interact
Muscles are attached to bone by tendons
A muscle must cross one joint to cause movement
A muscle can only pull in one direction
Muscles come in opposing pairs
Bicep - flex arm
Tricep - extend arm
Both of these muscles cross the elbow joint

5. Control of skeletal muscle contraction
Voluntary
Neurons near the muscle receive a message from the brain to contract
The electrical impulse from the neuron tells the muscle cells to contract
A muscle can do more work when more of its cells are told to contract

6. Skeletal muscle contraction
Muscle fibers are filled with protein cables called filaments
Myosin = thick filaments
Actin = thin filaments
When a muscle contracts
The myosin grabs onto the actin
The myosin pulls the actin toward the center
The muscle shortens (contracts)
The muscle relaxes when the myosin “lets go”
The energy for contraction
Is supplied by ATP
ATP is made from glucose and oxygen
When you run low on glucose and oxygen, the muscle becomes FATIGUED

7. Muscle contraction

8. Muscles and exercise Muscle tone
Muscles are in a state of partial contraction
Exercise
Aerobic
Heart, lungs more efficient
Weight training
When you lift weights you break the actin and myosin filaments
Your body then builds more
You gain strength and size
Bones get stronger
Proper exercise enhances CV health, strength, and flexibility